This invention relates to the removal of an introducer or cannula from a catheter, pacing lead, or similar item without having to pull the introducer over the proximal end of the catheter, and more particularly to a slitter device.
In my U.S. Pat. No. 4,214,594 there is disclosed a temporary lead assembly having a head portion for storing a cannula after the cannula has been used for extending the electrode end portion of the assembly into a body vessel.
U.S. Pat. No. 4,306,652 to Osborne discloses a flexible cannula that is made of a material having a molecular orientation whereby it will readily tear only in a longitudinal direction. As a result the cannula can be readily torn into two longitudinal sections for removal of the cannula from a catheter or similar device extending into a body vessel without having to slide over the proximal end of the catheter.
Another prior art cannula made to accomplish the same objects as that of the above Osborne patent is made of a different type material and has diametrically opposite score lines extending the length of the tubular part thereof to facilitate tearing the cannula into two axial half-sections.
A problem that at times is encountered with the cannulae referred to in the two preceeding paragraphs is that during tearing the cannula, one of the tabs together with the proximal part of the tube section joined thereto may break or otherwise separate from the more distal tubular part, or the cannula will not tear in a straight line and therefore not separate along the entire axial length of the tube section. As a result, it is necessary to use, for example a scalpel to cut the distal part of the cannula tubular portion. Using a scalpel may have adverse consequences, for example, cutting ones hand or the catheter.